Getting A Whiff Of DangerGetting A Whiff Of Danger

A new class of real-time sensors that can provide findings via the Internet may become part of a first line of defense against chemical or biological attacks on the nation's cities and critical infrastructure systems.

Researchers at the Sandia National Laboratories in Albuquerque, N.M., have developed sensors capable of detecting harmful contaminants in the ground and underwater, then automatically posting the results on an interactive Web site. The researchers are looking at ways the sensors can be deployed in reservoirs and water-distribution systems and adopted to other infrastructure.

The sensors use four different polymer films placed on custom-made microfabricated microcircuits, says Cliff Ho, a Sandia Labs researcher working on the project, which began prior to Sept. 11. They test for the presence of volatile organic compounds that cause the polymer films to expand at various rates, depending on the compounds' composition. The microcircuits note the variations in the expansion of the polymers as changes occur in electrical resistances. The result is distinctive chemical "signatures" that reveal the type of compound detected and its concentration.

The sensors can be linked via wired or wireless communications systems to a server, which log and display the results on a Web page. "Once it's on the Web, you get a virtually real-time monitoring capability from anywhere in the world," Ho says.

The sensors could be used in an effort by the federal government to monitor water supplies and tie together water utilities around the country via a nationwide information-sharing network. That effort is part of the federal Critical Infrastructure Protection program launched in 1998 to coordinate efforts of various agencies. It calls for the creation of multiple industry-specific information-sharing and analysis centers. These centers cover not only water utilities but also the country's telecommunications, electrical-, oil-, and gas-distribution systems, and other sectors such as finance and information technology.